Scientific Report

Abstract

The Kelt Reconditioning and Reproductive Success Evaluation Project is a research, monitoring, and evaluation (RM&E) uncertainties category project funded through the Columbia Basin Fish Accords. The objectives are to evaluate methodologies to produce viable artificially reconditioned repeat steelhead spawners and to determine the productivity of repeat spawners. Work occurs in both the Yakima and Snake river basins. We focused on collecting steelhead kelts at juvenile bypass facilities in Prosser and Lower Granite dams, and additionally some fish were collected at Dworshak National Fish Hatchery. These kelts were reconditioned (given prophylactic treatments and fed a specially formulated diet) at Prosser and Dworshak National Fish Hatcheries. Survival of long-term reconditioned kelts has been 42% (18 years) for Yakima River at Prosser Hatchery and 38% (6 years; 46% over the last 4 years) for mixed stock collections at Lower Granite Dam, and in previous years Fish Creek and the South Fork Clearwater River. Using estradiol assays, we have established that steelhead rematuration rates vary annually and spatially and ranged from 14.1% to 77.8%. We determined that kelts can remature as consecutive or skip spawners, typically returning to spawn in 5 or 6 months after kelting or 17 to 18 months later. A total of 98 reconditioned B-run steelhead were released below Lower Granite Dam in 2017 to address Reasonable and Prudent Alternative 33 of the FCRSP Biological Opinion. A total of 70 reconditioned, remature steelhead were released in the Yakima River in 2017. Mature reconditioned steelhead kelts were stocked in the Cle Elum Hatchery Spawning Channel in 2017, to evaluate the feasibility of using the facility to evaluate reproductive success in a more controlled setting. Evidence of reproduction was again confirmed but we continued to have difficulty capturing all juveniles in spawning sections. This was the last year that we will conduct the study in the channel and instead focus on reconditioned kelt wild reproduction. Reproductive success of reconditioned steelhead was confirmed in the Yakima River once again with assignments of 55 juvenile fish to 29 unique parents. Lifetime reproductive success for reconditioned kelt steelhead was estimated as 2.33 relative to single time spawning steelhead. Estradiol sampling of kelts has shown that they metabolically “decided” to consecutively remature or skip spawn after approximately 2 to 5 months after spawning. Consecutive and skip spawners due to the rigors of spawning and oogenesis, egg size is decreased but that energy is directed towards investment into individual offspring. Additionally, we discovered when fasting a portion of the fish that the “decision” to remature is hardwired into them and may occur even before spawning or shortly after. Fasting did reduce overall growth of fish and reduced the size and number of eggs that were produced. We continue to refine our plasma assays that detect IGF-I concentrations that we utilize for evaluating kelt maturation. We investigated if kelts could have cortisol signaling blocked, low sample sizes prevented obtaining statistically valid results, but we plan to continue to investigate in 2018. Evidence of homing fidelity to natal streams after reconditioning continues to be compiled for Yakima River and Omak Creek kelts based on both PIT-tag history and genotyping. From 2008 to 2017 we have detected conclusive evidence of 324 kelts showing strong site fidelity from both aforementioned waterways. Kelt reconditioning survival is good at multiple locations where it is being conducted, we continue to investigate how best to utilize the skip spawning portion of the life history. We drafted a Snake River Basin steelhead kelt reconditioning facility master plan, which was approved by the Northwest Power and Conservation Council (NPCC) in December 2016. Development of a Snake River kelt reconditioning facility final design has been ongoing with BPA in 2017 into 2018, once this has been completed the next steps in the ISRP 3 step process will be progressed. Development of a kelt population model continues to make progress with simulations of kelt reconditioning in the Snake River. The results of these simulations are preliminary and are built on extremely limited data sets, so results should not be considered definitive. The CRITFC and its member Tribes steelhead kelt reconditioning program continues to forward the science and inform the management of iteroparous O. mykiss in the Columbia River Basin. An extensive list of our work is compiled in the Adaptive Management and Lessons Learned section of this report. Also, our team produced 2 papers and given 11 professional presentations in 2017.

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CRITFC
Columbia River Inter-Tribal Fish CommissionOur mission is to ensure a unified tribal voice in the management of Columbia River basin fishery resources and to protect the reserved treaty fishing rights of our member tribes.